Increased stone fruit profitability by consistently meeting market expectations (SF12003)

What was it all about? 

Established in 2012 and concluding in 2017, this project was responsible for the establishment of the world-class Stonefruit Field Laboratory at DEDJTR-Tatura in Victoria, and through this the investigation of management practices to produce high-quality fruit and so increase grower productivity and profitability.

Investigations focused on the effect of orchard management practices involving crop load, irrigation, rootstocks and canopy architecture on improving consistency in fruit quality – including size, maturity and sweetness – for selected varieties of peach, nectarine, plum and apricot. To this end, the orchard involved a suite of field experiments, complemented with sensor technologies such as DA meters, plus a state-of-the-art post-harvest facility including a fruit grader equipped with near infrared spectroscopy (NIR) technology and optical sensors for rapid, non-destructive measurement of fruit quality, and cool rooms equipped with controlled atmosphere storage units.

Improvements in fruit size, maturity and sweetness were observed by manipulating fruiting levels by crop load management, applying strategic crop water stress through irrigation management, reducing tree vigour using dwarfing rootstocks and optimising fruit position in the tree by manipulating canopy architecture. Results suggest that careful manipulation of these agronomic practices in the correct combination has the potential to improve yield, pack-out and to reduce variability in fruit quality.

With the trees reaching maturity/commercial production in the 2017/18, a subsequent levy investment was to continue research to develop specific orchard management recommendations from the project’s many avenues of research. However, preliminary findings have suggested these approaches for growing consistent high-quality fruit:

• For new plantings of modern high-density orchards, select rootstock/scion and trellis design for early bearing
  
  
• Adjust crop load (fruiting level) to maximise fruit size and fruit sweetness to target market requirements…
  
  
• For peach and nectarine, a target cropping level of one fruit per 12 to 15cm of fruiting lateral, and
• Thin fruit (fruit <15mm diameter) early in the season to maximise cell number and final fruit size
  
  
• In cases where tree canopies have poor light distribution in lower parts of the tree, maximise fruit number higher in the tree and reduce fruit number at the base to improve fruit size and quality uniformity
  
  
• Apply regulated deficit irrigation (RDI) during stage two of fruit growth to maintain yield and fruit quality (the studies suggest, however, that deficit irrigation during stages one or three of growth reduce yield and fruit size)
  
  
• Monitor fruit size (using digital calipers) and maturity development (using DA meter) in situ (‘on the tree’) starting four to six weeks prior to harvest to determine optimal harvest date/s
  
  
• Regularly review orchard performance (e.g. irrigation, fertiliser strategies, IPM, yield, pack-out).

Throughout its course, the project delivered information to industry including through regional roadshows, conference presentations and ever-popular orchard walks and tours through the on-site facilities to showcase and provide training around modern high-density orchard management, including tree training systems, pruning, blossom thinning, IPM, irrigation and fertigation management and post-harvest storage and handling systems.

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All of the information, videos and resources produced by the project can be found at www.hin.com.au/projects/stonefruit-field-laboratory.

During its run, there were more than 30 YouTube videos were produced around project activities and findings, with some of the concluding videos including:

• Results of crop load management experiments (7 mins)
• Results of irrigation experiments for high-quality fruit (9.5 mins)
• Orchard establishment for high-quality fruit (3.5 mins)